Mesothelioma

What is mesothelioma?

Mesothelioma refers to tumors that develop in the mesothelium, a type of tissue that makes up the lining of cavities or hollows that protect and surround certain organs. This tissue forms:

• The pleura, which surrounds your lungs.
• The peritoneum, which surrounds the organs of your abdomen and pelvic area.
• The pericardium, which surrounds your heart.
• The tunica vaginalis, which surrounds your testicles.

Most people think of cancer of the pleura when they hear the word mesothelioma. This type of mesothelioma is related to exposure to asbestos and is often cancerous.

What are the types of mesothelioma?

There are different ways to refer to mesothelioma. One way is to determine if the tumor is cancerous (malignant mesothelioma) or not cancerous (benign mesothelioma). Other types refer back to the cavities formed by mesothelial tissue and are called:

• Pleural mesothelioma.
• Peritoneal mesothelioma. You might also hear this called abdominal mesothelioma.
• Pericardial mesothelioma.
• Mesothelioma of the tunica vaginalis testis. You might also hear this called testicular mesothelioma.

Mesothelioma may also be divided into groups based on the type of cell that creates the tumor. These types are:

• Epithelioid. This type of cell usually has a better prognosis than the others. Epithelial cells are the most common cells in your body.
• Sarcomatoid. Sarcomatoid cells are the least common cells in your body. Their shape makes them more likely to move elsewhere in your body because it’s harder for them to stick together. This makes them more dangerous.
• Biphasic. This is a mix of the first two types.

Who does mesothelioma affect?

Mesothelioma is associated with exposure to asbestos, a naturally occurring mineral used in many industries. Its use is now regulated in the U.S. and safety measures are in place, but this hasn’t always been true. People who were exposed 20 to 40 years ago are only now being diagnosed.

More men than women are affected by mesothelioma, at a rate of 3 to 1. Men in their 50s to their 70s represent most of the diagnoses.

Workers in the following industries were, and possibly still are, more at risk due to increased exposure to asbestos products:

• Construction, roofing and demolition of buildings (asbestos is used in insulation and some tiles).
• Shipbuilding.
• Mining.
• Milling.
• Mechanics. (Asbestos is used in brakes).

Military veterans may have been exposed in many ways at military bases, on ships and in construction.

In childhood mesothelioma, asbestos doesn’t seem to be an issue. Children who have had earlier types of cancer and have been treated with radiation therapy have a higher risk of developing mesothelioma.

How common is mesothelioma?

Mesothelioma is considered a rare illness. Currently, there are an estimated 3,000 to 4,000 new cases of mesothelioma in the U.S. each year. Of the total, there are about 2,500 cases of malignant pleural mesothelioma.

What are the symptoms of mesothelioma?

You can have mesothelioma without symptoms, and you can have different symptoms depending on the type of mesothelioma you have. If you have any of the types of mesothelioma, it’s possible to have:

• Fever.
• Night sweats.
• A general feeling of being unwell, also called malaise.
• Weakness.
• Unintended weight loss.

Signs and symptoms of pleural mesothelioma

• Shortness of breath (dyspnea) that comes on slowly and gets worse over time.
• Chest pain.
• Difficulty swallowing (dysphagia).
• Lumps in the chest area.
• Fluid on the lungs (pleural effusion).

Signs and symptoms of peritoneal mesothelioma

• Abdominal pain.
• Anemia.
• Abnormal fluid collection (ascites).
• Diarrhea.
• Loss of appetite and loss of weight.
• Nausea and vomiting.
• A blockage in the small intestine.

Signs and symptoms of pericardial mesothelioma

• Low blood pressure.
• Abnormal heart rhythm patterns.
• Chest pain.
• Trouble breathing.

Signs and symptoms of mesothelioma of tunica vaginalis testis

• Hydrocele (swelling in the scrotum caused by fluid collection).
• Lump in the scrotum.
• Inguinal hernia.
• Spermatocele (cyst in the epididymis).

What causes mesothelioma?

In adults, the main cause of mesothelioma is past exposure to asbestos fibers and dust. Between 70% and 80% of people with mesothelioma were exposed to asbestos, mostly through work. It takes over 20 years for symptoms to develop.

In smaller numbers, people have developed mesothelioma after exposure to similar minerals like silica and erionite. Erionite is a type of mineral (zeolite) that’s been linked to mesothelioma.

Scientists are also investigating whether your genes contribute to your risk of developing mesothelioma. This is because only a small number of people who have been exposed to asbestos have developed mesothelioma.

Scientists are also looking into other causes, including exposure to chemicals, having viral infections and having radiation. Additionally, radiation therapy is associated with childhood mesothelioma.

How is mesothelioma diagnosed?

Your healthcare provider will take your medical history and do a physical examination. Hearing your symptoms and listening to your chest will provide the first clues. Your provider will probably order a series of tests to make their diagnosis. These tests may include:

• Blood tests.
• Lung function tests.
• Imaging tests, including chest X-rays, computed tomography (CT) scans, positron emission tomography (PET) scans or, less often, magnetic resonance imaging (MRI) scans.
• Biopsy.

How is mesothelioma treated?

Treating mesothelioma depends on what type you have. Treatment is different for benign (noncancerous) mesothelioma than it is for malignant mesothelioma.

Treatment for benign mesothelioma

Benign mesothelioma tumors aren’t cancerous and don’t spread (metastasize) to other parts of your body. They can grow in the pleura, in your abdomen and in the reproductive organs of men and women. Typically, your healthcare provider will remove them in a surgical procedure. They usually don’t come back if they are completely removed. Some providers might suggest further treatment with chemotherapy in the case of some types of benign mesothelioma.

Treatment for malignant mesothelioma

After you’ve been diagnosed with mesothelioma, your healthcare provider will use the information they have to assess how far the disease has progressed. This assessment is called staging and refers to cancers. Higher staging numbers typically mean that the disease has progressed, such as Stage III or Stage IV disease.

The most common type of cancerous mesothelioma is malignant pleural mesothelioma. But for all types of malignant mesothelioma, your options may include surgery, with or without chemotherapy or other therapies, or chemotherapy, radiation therapy and other types of therapy without surgery.

If your provider stages your tumor and you’re able to have surgery, you’ll have surgery to remove the tumor. However, less than 33% of people with malignant pleural mesothelioma can have this type of surgery. You may or may not have chemotherapy or radiation therapy as well.

If you can’t have surgery, the tumor is treated with chemotherapy and/or radiation. You may have an option to try treatments that are being studied, such as biologic agents and antiangiogenic therapies. Antiangiogenic treatments try to destroy cancer by making sure it doesn’t have a blood supply.

Complications of treatment for malignant mesothelioma

Even though surgery and chemotherapy might be the best course of treatment, they may have complications such as:

• Infection.
• Heart attack (myocardial infarction).
• Kidney failure.
• Failure of more than one organ system.
• Inability to get off a ventilator (a breathing machine).

How can I prevent mesothelioma?

The best way to prevent mesothelioma is to avoid asbestos and other harmful minerals. If you must be around asbestos, be sure to follow the guidelines for protective masks and clothing.

What can I expect if I have mesothelioma?

The prognosis for any type of malignant mesothelioma is poor. Many people die in the first four to six months after diagnosis and most by 12 months after diagnosis. However, some people have lived longer than that and a rare few were alive at the five-year mark.

When should I see my healthcare provider?

If you’ve been treated for malignant melanoma, your mesothelioma specialist will probably want to see you on a specific schedule. You’ll also want to see your primary care provider too. These providers will monitor your overall health and may do tests to see if cancer returns.

Ask, too, about ways to improve your life if you're having side effects of chemotherapy and radiation. There may be more options than you think.

Make sure that you know when you should contact a healthcare provider immediately — for instance, if you have a fever or extreme dizziness. Then, follow those suggestions. It’s always OK to contact your provider with any questions you might have.

Is mesothelioma always fatal?

Benign mesothelioma, or mesothelioma that isn’t cancerous, isn’t fatal. However, malignant mesothelioma is almost always fatal.

Part of the reason that malignant mesothelioma is so deadly is that it grows without symptoms for years. Another reason is that current treatment options aren’t that successful at treating the disease.

What is the life expectancy of a person with mesothelioma?

There are many different types of mesothelioma, so life expectancy estimates vary. And people are all different in terms of age, general health and other medical conditions. As always, you’ll probably have better results if mesothelioma is found early and treated as vigorously as possible.

A note from Cleveland Clinic

If you are someone who used to work with asbestos and you have trouble breathing, make the call to your healthcare provider to get checked out. If you do find out you have mesothelioma, work with your healthcare team to develop a plan for each type of possible outcome. This can mean getting as much information as you can and speaking to family and friends about what’s going on. You might find it useful to join a support group or get some counseling. You might want to be involved in clinical studies if you can. Your healthcare team will provide support and information.